I often use scales played in opposite directions to reinforce posture and the body’s ability to lean in either direction toward the highest or lowest octave without bench wandering, or dizzying head movements.
Since the third octave in these excursions is not within eye range, the advantage of a pull toward the keyboard, (even without visually focusing on an extreme octave at the turnaround, seems to bring the whole keyboard “closer” to the player.) However, in an early stage of learning, I recommend that a student lean toward the highest or lowest octave at the terminus, and gradually return to a central position during the progression back to start. (tonic)
Ideally, an underlying goal is to “feel” the transit of notes (preferably in “groups”) without having to check on what’s happening at any opposite juncture of the scale.
To this end, I’ve enlisted “blocking” routines to embed the topography of a particular scale that supports a “tactile” sense of the journey. Naturally, where fingering symmetries occur between the hands, the undertaking becomes less complex.
Scales in parallel motion that begin with finger no. 5 in the Left Hand, and thumb in the Right Hand will have the same fingers playing simultaneously in CONTRARY motion, though the terrain traversed will vary according to the key signature. Same finger symmetry will be easily assimilated with all white note scales such as C Major and A minor (Natural form). These can easily foster an eyes closed rendering with less distraction. (For some students, sharp and flat keys create anticipatory anxiety, a tightening of wrists, and overall tension. That’s when side-to-side head movements intensify, increasing confusion.)
Blocking Techniques to advance fluidity
Taking ‘A’ minor Natural as my springboard, I created a tutorial that demonstrates “blocking” or “chunking” notes between the thumbs with an awareness of floating arms, supple wrists, and light, “buoyant” thumbs between clusters. As the hands part from the home tone, traveling concurrently to the highest and lowest octave, there’s a coordinated lateral motion without abrupt twisting or misalignment, as “buoyant,” featherlight thumbs swiftly shift under blocked notes. (Note: The singing tone is preserved in these blocking escapades)
Meanwhile, at the turnaround, a lateral rotation prevents an angular attack while an ensuing “loop” over the thumbs to chunks in each hand inspires a quick advance of thumbs from their temporarily tucked under position. In these maneuvers, thumbs have a “guide” role in conjunction with hand/arm rotations. (Techniques of blocking are more definitively illustrated in my video tutorial)
Finally, unraveling groups of notes in stepwise sequence becomes a natural outflow of the scale’s geography.
However, it’s not enough to have a group note sense of a contrary motion scale because phrasing and well-shaped lines are important ingredients of musical expression. Embedded into consciousness is the imagined tone (hear it before you play it), and how weight transfer, a supple wrist and the floating arm work harmoniously through three fluidly rendered octaves. (Scales should not be robotically played, or shelved as meaningless exercises. Their execution with finesse feeds directly into repertoire study)
Staccato playing in Contrary motion
Crisp, detached playing is a nice outgrowth from a well-contoured legato rendering. In the staccato cosmos, a consciousness of “GROUPS” or unraveled clusters of notes in transit creates a common bond between various executions of staccato. In very rapid tempo, I might choose finger generated staccato, leveraging my arm weight pressure for dynamic variation. (The tips of my fingers have crisp releases without freezing my wrists or other parts of my arm.) With wrist staccato, I might better shape or phrase “groups” of notes with mild wrist undulations (or dips) through them. For a very forceful, accented, Forte to double Forte I will feel my hands lifting off the keys with forearm impulses reinforcing note to note transit. In all staccato forms, I will want to sense a common HORIZONTAL movement of lines that are naturally breathed and well-spaced.